Process of reducing milk to a dry powder.



PATENTED OCT. 30, 1906.

L. GATHMANN. Paoosss OF REDUCING MILK TO A DRY POWDER.

APPLICATION FILED OOTJB. 1904.

' T a/ZZ whom, it may concern:

LOUIS GATHMANN, OF WASHINGTON, DISTRICT OF COLU-MBIA, ASSIGNOR OFONEI-HALYF TO MELVILLE E. DAYTON 'WASHI NGTON, DISTRICT OF COLUMBIA.

AND HOWELL ,IBARTLE, or

t I PRQCESS OF REDUCING MILK TO A DRY POWDER- Specification of Letters Patent.

Patented Oct. 30, 1906.

I Application filed October 18, 1904. Serial Nb- 228.956.

. Be it known that I, LoUIs GATHMANN, a-

citizen of the United States, residing at ing milkv to a dry powdered form by evapo- Washington, in the District of Columbia, have invented-a new and useful Process of Reducing Milkto a Dry Powder, of which the following is a specillcation My invention relates to a process of reducrating the water therefrom for the purpose of preserving the solid constituents in a dry and practically-unchanged condition, so that by the addition of water thereto the complete or substantially complete milk may be reproduced.

It has heretofore been proposed to evaporate thewa'ter from milk by feeding the milk in a thin film upon arotatirig steam-heated cylinder, from ,which the dried or partiallydried product is to be removed by a suitable scraper. In the practical operation of this method it has been found that the film becomes hard pr glazed on its exposed surface before the moisture has been entirely evaporated therefrom and that completeevaporation is thereby retarded, if not effectually prevented. i

The main object of my invention: is the economic production of a better and more uniform product by effectually and equally subjecting all portions of the mifkor milklike substance torapid evaporating influences and, in effect, to prevent the formation of a hard surface on the material treated.

Broadly stated, my process consists in heating the milk in a comparatively thin layer to evaporate the water and simultaneously'subjecting it toa grinding action,

so that all portions of the solidconstituents of the milk will be thoroughlyworkedend equally exposed to the action of 'the heat for vaporizing the water. In carrying out my process the milk is poured or fed to or upon v a surface which is heated above the boiling and moved. relative "point of water, and while uponsaid'heated surface it is subjected to a ding action, preferably by means of anot er heated surace which is brou ht in contact therewith lg thereto. The milk is quickly concentrate by thevaporizing heat and soon changes from a liquid to a semiliquid or pasty'form and then to a 'pow dered form. The continuous action causes all of'the solid constituents of the milk to be thoroughly worked or kneaded during the drying process and to be thereafter ground into powdered form as the stage of complete dryness is approached. "l'he heat employed should be'between 212 and 270 Fahrenheit.

My process is in the best practice, made continuous by means of suitable apparatus to be hereinafter described in which the milk is continuously fed 'to a highly-heated moving or revolving surface; but it is not necessarily fed thereto in the form of a thin film, as in the prior process hereinbefore referred to; and for this reason a greater quantity of milk may be treated in a given time upon a possible 79 given area of heated surface than is in the prior method referredto.

In the accompanying drawings I have illustrated amachine which may be used for continuously carrying out my rocess;

but it is to'be distinctly understood t at said process is not dependent upon any particular form of apparatus.

In said drawings, Figure 1 is a central vertical longitudinal section, and Fig. 2a

vertical cross-section, of the machine re- 80 ferred to.

A represents a hollow cone 'which'is rota tably mounted in a concave B, the inner surface of the latter conformin and bein in@ close proximit with the su ace of the 01-18 5 low cone, sai concave being closed at its lar er end by a wall I) and open at its smaller 1 en as clearly shown in Fig. 1. The surface of the cone is spirally grooved or corrugated,

asshown at a, and the adjacent surface of 0 p the concave is similarly corrugated,- as at b, Y but in an opposite directlon to the corrugations on the surface of the cone, as is common in grinding-mills, so that when the cone is revolved the solid constituents of the milk 5 will be kneaded and ound between the two' surfaces and graduall the corrugated surface of the cone to. the smaller or dischar eend of the machine The cone is pre? a temperature above the boiling-point of water, the steam entering the interior of the cone by way of a pipe and be' discharged, together with the water of con ensation, by

way of a pipe 0. I prefer also to heat the p05 grinding-surface of the concave B, and for y carried or pushed by erably heated by steam to I00 this purpose said concave is;jacketed toafford a steam-s ace N, which is provided with suitable in et and discharge pipes b and b, as clearly shown.

Above the cylinder is a hopper D, from which the milk is fed in a continuous stream to the heated surface of the cone at or near the larger end thereof, said hopper being provided with a discharge-aperture d, which may be increased or diminished in size by a slide d for regulating the flow of milk therefrom, as will be readily understood.

In the o erationof the apparatus the quan tity of mi k fed to the machine will depend upon the diameter and length of the cone A. Said cone may be revolved in any suitable manneras, for instance, by means of a pulley e, connected by a belt to a suitable source of power. The cone is revolved in the direction indicated by the arrow in 'Fig. 2 and as milk is fed thereto from the hopper D the main bulk of the water is uickly vaporized by the heat from the cone, t e solid constituents of the milk, together with the remaining moisture, being carried by the cone into contact with. the corrugated surface of the concave B. The material under treatment rapidly assumes a utty-like consistency and as the cone is revo ved is worked or kneaded between the heated corrugated surfaces of the cone and concave, As the spiral corrugations on the two surfaces run in op osite directions, the material is pushed or creed toward the smaller end of the concave, and as it approaches complete dryness it is round between said surfaces and finally disc arged from the machine into a suitable receptacle .F in a dry powdered form.

v A brush G is arranged in contact with the cone between the feed-hopper and the discharge end of the apparatus for releasing such of the material under treatment as may adhere to the grinding-surface of the cone. It is also desirable to provide the apparatus with a series of dashboards g to receive such of the milk as may s lash from the cone as the milk is being fed rom the hopper and direct it back on the cone.

Having described my process, what I claim as new, and desire to secure by Letters Patent, is-

1. The herein-described process of treating milk to reduce the same to a dry form for better reservation, which process consists in heatlng the milk in a comparatively thin layer to evaporate the water, and subjecting it to a kneading, which gradually merges into a grinding action as the milk solidifies, to form a owder.

2. The erein-described process of treating milk to reduce it to a dry form, which process consists in feedin the milk to or upon a surface which is heate above the boilingpoint of water so as to form it into a comparatively thin la er u on said surface, and subjecting it to a nea ing, which gradually merges into a grinding action as the milk solidifies, to form a powder.

3. The herein-described process of treating milk for reducing it to a dryform, which process consists in orming the milk into a comparatively thin layer by feeding it to or upon a continuousl -m'oving surface, heating it to evaporate t e water, and simultaneousl subjecting it to a kneading, which gra ually changes to a grinding action, as the milk solidifies, to form a powder.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

- LOUIS GATHMANN. Witnesses C. W. FOWLER, A. E. POWELL, 

